Non-missile intracranial traumatic penetration of a foreign body is very rare. We report a rare case of traumatic calvarial stone with review of the literature.

A 35-year-old male patient presented with alleged history of road traffic accident-while riding a two-wheeler without a helmet, he hit a divider and fell down. He had recurrent vomiting. Neurologic examination revealed amnesia for the event with Glasgow Coma Scale (GCS) score of 15/15. In addition he had left clavicle fracture and an irregular lacerated wound in the left parietal region. Skull X-ray [Figure 1] and cranial computed tomography (CT) [Figure 2]a and b showed left frontoparietal linear fracture and presence of a foreign object. Scalp wound was cleansed with normal saline solution, hydrogen peroxide and povidone iodine and an immediate surgical exploration, 5 × 4 cm craniectomy was done along with removal of comminuted depressed fracture fragments and the foreign object. The foreign object was visualized and identified as a stone (3 cm×3 cm×2 cm) embedded in the parietal fracture [Figure 3]. The inner layer of the dura was found intact. The operative field was irrigated with saline and antibiotic solution. He was put on injectable antibiotics for the first five days followed by oral antibiotic till suture removal. Postoperative course was uneventful and he was discharged on postoperative Day 7. After three months he had methyl methacrylate cranioplasty for the cranial defect.

Figure 1: X-ray skull lateral view showing linear fracture located in frontal and parietal bones along with well-defined hyperdensity at the parietal region

Penetrating head injuries (PHIs) most commonly occur due to high-velocity ballistic weapons and firearms. Non-missile injury is the injury caused by objects with an impact velocity less than 100 m/s. [1] Penetrating head injuries by non-missile low-velocity particles constitute a rare subgroup with the primary pathology being tissue laceration, whereas in missile injuries cavitations and shock waves cause additional tissue damage. [1]

One of the consequences of penetrating is infectious complications. In the national survey of penetrating injuries by Kaufman et al., [2] the incidence of infectious complications was 64% and brain abscess was 48% despite treatment with antibiotics. Early debridement with complete removal of foreign body along with bony fragments was recommended. [3] PHIs can result in death in 40% of cases because of damage to important structures, major vascular injury, concussion, blast injury, or infection. [4],[5]

Incidence of post-traumatic seizures is higher with penetrating head injuries compared with closed head injuries. Seizures occur in 50% of patients with penetrating trauma in a study with a follow up period of 15 years. [6] Prophylactic antiepileptic drugs are recommended in those cases in which traumatic brain lesions are evident, such as intracerebral hemorrhage, subdural hematoma and depressed skull fracture. [7] Post-traumatic epilepsy occurs more likely in cases with injury to the parenchyma. [4] Prophylactic antiepileptic drug use has no effect on the development of late epilepsy. Most patients who have not had a seizure within three years of penetrating head injury will not develop seizures. [3]

Cranial bone CT is the most important study to detect foreign objects as small as 0.06 mm and is also useful in identifying hematoma, plotting the trajectory and identifying the calvarial defect. [5] There are eight similar reports of PHI by a stone in the literature. [7] PHIs are severe traumatic injuries, have high risk of morbidity and mortality, particularly compared to closed head injuries. Immediate transport to a specialized trauma centre is mandatory. Early surgery is most important. Surgery includes complete removal of foreign body along with bone remnants, watertight dural closure and evacuation of hematoma. It is crucial to prevent any uncontrolled movement of the foreign body which could increase the damaged area. Failure to identify the foreign body early results in poor outcome. The outcome depends on the severity and location of the initial injury, the rapidity of operative exploration and debridement, and the avoidance of delayed secondary injury.